Northern Ireland on Monday marks the 25th anniversary of its landmark 1998 peace accords, with the UK province mired in political dysfunction and security concerns that threaten to overshadow the milestone. No major public events are planned for the day itself, but British Prime Minister Rishi Sunak and US President Joe Biden will arrive Tuesday to launch several days of high-profile commemorations. The territory has been reshaped since pro-UK unionist and pro-Irish nationalist leaders struck an unlikely peace deal on April 10, 1998 — Easter Good Friday — following marathon negotiations. Brokered by Washington and ratified by governments in London and Dublin, the Good Friday Agreement largely ended three decades of devastating sectarian conflict in Northern Ireland and intermittent terrorist attacks on mainland Britain. The so-called “Troubles” killed more than 3,500 people. They pitted the province’s majority Protestant unionists, wanting continued British rule, against Catholic republicans demanding equal rights and reunification with the Republic of Ireland. But a quarter-century on, Northern Ireland is struggling to consolidate the gains of its hard-earned peace, with post-Brexit trade arrangements prompting political instability, and violence by dissident republicans on the rise. “While it is time to reflect on the solid progress we have made together, we must also recommit to redoubling our efforts on the promise made in 1998 and the agreements that followed,” Sunak said in a statement marking Monday’s anniversary.